Amelia Implementation Engineer interview questions

Consisted of 5 rounds of interviews, including initial HR screen, extended technical phone interview, two separate 1:1 on-site technical interviews with other engineers and a final interview with the manager. Each round is around 40-minutes to an hour long. Everyone was friendly. They ask for paperwork with references and a projected salary range that's also discussed at the onset. As I progressed through each round to the final interview I fully believed I was going to land an offer. I was given an office tour and met potential colleagues/peers after the first round of on-site interviews. During and after the final on-site interview (with a manager) I was consistently spoken to in terms of how I would contribute to the team and fit in and how I'd do extremely well in the position. Two nerve-wracking days later and at the end of the week I fully expected a phone call with an offer, instead I received a last-minute generic form-letter rejection via email. I was blindsided to say the least.